Conventional recording heads for linear tape drives have small transducers incorporated into a large head assembly to span the full width of the tape. For recording heads fabricated using thin-film wafer technology, this requires that the head either be fabricated individually on a wafer which is at least as wide as the recording tape and lapped individually to the proper shape, or be fabricated as a small part and assembled with larger pieces and the full assembly lapped individually to the proper shape.
Prior art FIG. 1 illustrates a wafer 100 on which a plurality of heads 102 may be manufactured. As shown, the wafer 100 includes two columns of multiple rows of heads 102. During the fabrication of the wafer 100, an array of heads 102 including transducers and auxiliary circuits are fabricated on a common substrate in a deposition of metallic and non-metallic layers. The auxiliary circuits are sometimes referred to as electrical lap guides (ELGs). Patterning of the array of transducers and ELGs is accomplished using photolithography in combination with etching and lift-off processes. The finished array or wafer is then optically and electrically inspected and subsequently cut into smaller arrays of heads 102. Next, individual heads 102 are machined, at a surface 106 which will eventually face the recording medium, to obtain a desired transducer height (sometimes referred to as the stripe height (SH) or to obtain a desired inductive transducer height sometimes referred to as the throat height (TH).
Prior art FIG. 2 illustrates a wafer 200 including a plurality of strips of closures 202 attached thereto. Such closures 202 define a plurality of slots 204 in which the aforementioned contacts 206 associated with the ELGs reside. Such closures 202 have recently become a common part of wafer processing in view of the benefits they afford in resultant heads. More information on the manufacture and use of closures 202 and the related benefits may be found with reference to U.S. Pat. Nos. 5,883,770 and 5,905,613 which are incorporated herein by reference in their entirety.
Prior art FIG. 3 illustrates one of the heads 300 set forth in FIG. 1 with a closure 302 attached thereto. As shown, the present head 300 is detached from a wafer. Since the head 300 is generated from a wafer structure, the head 300 is extremely thin in shape and form. In order to increase the stability of the head 300 for the suitable use thereof, the head 300 must be attached to a beam 304 of some sort formed of a rigid material. Such beams 304 are often referred to as a “U-beams.” One stringent requirement in attaching the head 300 to an associated beam 304 is that the relative position of the head 300 and beam 304 be precisely aligned. Absent such alignment, the operation of the head 300 may be compromised.
There is thus a need for a method and apparatus for the precise attachment of a head 300 and a beam 304.
Yet another problem arises when attempting to dice the heads 300 on a wafer. In the prior art, a traditional magnetic head saw blade may be used to cut the heads 300 from the wafer. Recently, however, the use of the closures 302 such as that shown in FIG. 3 has complicated such process. In particular, the increased thickness of the material to be cut has been increased since a slight portion of the closure 302 must also be diced.
FIG. 4 illustrates a prior art saw blade 400 in the process of dicing a head 402 equipped with a closure 404. As shown, the increased thickness of the combined head 402 and closure 404 cause the blade to slightly bend due to the cutting forces resulting from cutting the additional material. This bending, in turn, results in non-planarity in the operating surface 406 of the head 402.
There is thus a need for a method and apparatus capable of dicing a head equipped with a closure while maintaining the planarity of the head operating surface.
FIG. 5 is an end view illustration of one particular type of bidirectional tape head. As shown, a head 560 is provided with a flat transducing surface 561 and a row of transducers on the surface of gap 562. An electrical connection cable 563 connects the transducers to the read/write channel of the associated tape drive. Alumina overcoat 564 protects the transducers and forms a slope discontinuity edge with respect to the flat transducing surface 561. A slope discontinuity edge 565 is formed parallel to the gap 562 at the side of the flat transducing surface 561 opposite the gap surface.
To control the overwrap angle of the tape 566 at edge 565, an outrigger 567 is provided. The outrigger 567 may be formed by cutting a groove 568 in the head 560. A taper 569 may be lapped on the outrigger 567, preferably at an angle about midway between the expected wrap angles the head will be presented with for various cartridges. The depth of the taper 569 is controlled so that the line from edge 565 to edge 570 is at the desired overwrap angle with respect to the flat transducing surface 561.
The head penetration into the tape 566 of a cartridge is controlled so that at the minimum wrap angle 571, the tape just touches the edge 570. Thus, for various cartridges, the tape wrap can move between the positions indicated by 571 and 572, while the outrigger 567 maintains a constant wrap angle onto the flat transducing surface 561. More information on the head design shown in FIG. 5 may be found with reference to U.S. Pat. No. 5,905,613, which is incorporated herein by reference in its entirety.
Unfortunately, the above design requires two actions to afford the accompanying benefits, namely the cutting of the groove 568 and the lapping of the taper 569. As is well known, each action that is required during the process of thin-film magnetic head manufacture creates much expense.
There is thus a need for a technique of affording the benefits of the groove 568 and taper 569 of FIG. 5, with less of a manufacturing expense.